This is a double-blind, randomized, placebo-controlled trial of daily oral genistein in 24 men initiating Androgen Deprivation Therapy (ADT) for prostate cancer (PCa). Genistein is a natural supplement that comes from soy. The purpose of this study is to see if genistein has any effect on preventing or reducing heart disease and diabetes risk in men receiving ADT for PCa. A combination of nutritional measures, blood markers and imaging tools will assess body composition, lipid levels and insulin resistance. Information from this study will increase understanding of interventions which may prevent or reduce health risks during prostate cancer treatment.